Re: [Xen-devel] xen/acpi: ACPI memory hotplug

["Liu, Jinsong" <jinsong.liu@xxxxxxxxx>]

Dan Carpenter wrote:
> Hello Liu Jinsong,
> 
> This is a semi-automatic email about new static checker warnings.
> 
> The patch 259f201cb7ea: "xen/acpi: ACPI memory hotplug" from Jan 24,
> 2013, leads to the following Smatch complaint:
> 
> drivers/xen/xen-acpi-memhotplug.c:198 acpi_memory_get_device()
>        error: we previously assumed 'device' could be null (see line 171)
> 
> drivers/xen/xen-acpi-memhotplug.c
>    170
>    171                if (!acpi_bus_get_device(handle, &device) && device)
>                                                              ^^^^^^
> New check.
> 
> Btw, checking device is unnecessary.
> 
>               if (acpi_bus_get_device(handle, &device) == 0)
>                       goto end;
> 
> A successful "Get Device" means that "device" is non-NULL; that's
> built into the name.  Anyway, if acpi_bus_get_device() fails either
> something else will fail or we will Oops in the call to
> acpi_driver_data(). 
> 
>    172                        goto end;
>    173
>    174                status = acpi_get_parent(handle, &phandle);
>    175                if (ACPI_FAILURE(status)) {
>    176                        pr_warn(PREFIX "Cannot find acpi parent\n");
>    177                        return -EINVAL;
>    178                }
>    179
>    180                /* Get the parent device */
>    181                result = acpi_bus_get_device(phandle, &pdevice);
>    182                if (result) {
>    183                        pr_warn(PREFIX "Cannot get acpi bus device\n");
>    184                        return -EINVAL;
>    185                }
>    186
>    187                /*
>    188                 * Now add the notified device.  This creates the 
> acpi_device
>    189                 * and invokes .add function
>    190                 */
>    191                result = acpi_bus_scan(handle);
>    192                if (result) {
>    193                        pr_warn(PREFIX "Cannot add acpi bus\n");
>    194                        return -EINVAL;
>    195                }
>    196
>    197        end:
>    198                *mem_device = acpi_driver_data(device);
>                                                ^^^^^^
> Dereference.
> 
>    199                if (!(*mem_device)) {
>    200                        pr_err(PREFIX "Driver data not found\n");
> 
> regards,
> dan carpenter

Thanks Dan, updated, will send out minutes later.

Regards,
Jinsong
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel